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  3. Diagnostics and Troubleshooting

Diagnostic tools

If errors occur on your server, it is recommended that you first diagnose the problem yourself. Diagnostic results will speed up the troubleshooting process by our specialists or allow you to troubleshoot problems without outside help.

Command line in different OS

For diagnostics, the command line of the operating system is used.


In the Windows operating system, the command line is launched by the combination Win + R (or Start-Run). Next, enter cmd in the window that opens and click OK. This will open the Windows Command Line.

Next, enter the command and press Enter to execute it.

To copy text from the command line, select it with the mouse and press Ctrl + C. The text will be copied to the clipboard and can be pasted when sending messages to support.


Working with the command line in Linux is done in the Terminal application. To start, press Ctrl+Alt+T or type in the search "terminal".


MacOS uses:

  • Terminal.
  • Network utility (ping, nslookup, traceroute). Both utilities can be found via Spotlight/Finder.

Basic commands


The ping command displays the response time of the specified resource. Type ping and the domain name (or IP address) of the resource at a command line. Then press Enter.

ping my.domain.com


The tracert command traces the path of packets from the host to the destination.

Enter the command and domain name, press Enter:

 tracert my.domain.com


The nslookup command queries for information about DNS servers. This allows you to independently check or report the information received to technical support.

Enter the command and domain name, press Enter.

nslookup domain.ru


The telnet command is used to check individual services (usually mail servers).

If as a result of executing the telnet command you receive the message "telnet is not an internal or external command ..." - telnet is not activated. To activate enter:

dism /online /Enable-Feature /FeatureName:TelnetClient

To test the connection to the outgoing mail server, enter:

telnet smtp.inferno-solutions.com 25

Or specify a different port, 2525 or 465, if you are experiencing problems with it. How SMTP works?

To test the connection to the incoming mail server, enter:

telnet pop3.inferno-solutions.com 110 (or 995)

telnet imap.inferno-solutions.com 143 (or 993)

Connected to inferno-solutions.com  - successful connection

Unable to connect to remote host – most likely, the connection to the specified port is blocked by the provider or administrator. Also, the port can be blocked by antivirus software or a firewall.

If you have any questions, please create a ticket to technical support.